Research On The Thermal Environment Of Typical Landscapes In Beijing

The urban heat island effect has significant impacts on human living conditions. The urban thermal environment is changing as the population aggregation and built-up expansion, particularly in metropolitans such as Beijing, London. Osaka and New York. The thermal environment would be more deteriorative under the background of global climate change in recent years. Beijing is a large metropolis characterized by high population density, complex landscape pattern, intensified energy consumption, and developed urbanization. The thermal environment of Beijing is important for urban design and planning. This study researched the thermal environment of different kinds of landscape in urban functional areas. The results would provid scientific evidence for improving the living condition and outdoor environment in Beijing and other cities.Using automatic meteorological datas in Beijing stations, the basic characteristics of urban heat island intensity in Beijing have been studied, including annual, monthly, seasonal variations, as well gradient distribution. And then, a serious of monitoring land surface, near land surface environment have been conducted in urban parks, commercial, campus, housing and river corridor, October 2013～October 2014. This paper focus on the temporal and spatial distribution of thermal environment among city, suburban and suburb-outer, studies the following aspects of landscapes in urban functional zones, and draw the preliminary conclusions:(1) The yearly variations both in Beijing and Miyun metrology station show that, annual mean temperature of them are 0.2℃/10a:During the year of 1991～2011, the urban heat island intensity curves ranges 0.8～1.8℃, fluctuating slow and small amplitude. The lowest temperature of urban is higher than that in rural. Automatic meteorological station observation data from January 2014 to may show that, the decreasing air temperature is Tiananmen、The Tiantan Park、 Guanyuan、The Zizhuyuan Park、Gongren Gym、The Sun Park、The World Park、The Forest Olympic Park. Suburban parks are answer to sporting, having a rest, getting together and so on.(2) The thermal environment characters of typical landscapes had monitored in urban functional areas, appointed that the irrational landscape pattern accounting for the high temperature. Comparing the characteristics of mean land surface and air temperature, humidity of landscapes, road superiors the forest and grass. Urban park is lower temperature than building lots. The complicated relationship between land surface and air temperature reflects the landscape heterogeneity. It is not sensitive to relative humidity index reflect the environmental changes, even if the season change and urban functional zones different.(3) The result showed that the cooling effect of rivers is effective in a width of 20-30m. This cooling effect is significant in a 50m distance from the river. The temperature of road is lower than that in other urban functional areas, river can reduce the thermohygrometric index and increase human comfort.